Second to fourth digit ratio (2D:4D) of the right hand is associated with nociception and augmenting-reducing

The ratio of the length of the second and fourth fingers (2D:4D) represents an individual difference variable putatively related to prenatal testosterone exposure. Previous research found significant associations between this variable and sexually dimorphic and other sex-hormone mediated traits like fertility, masculinity, spatial ability and sensation seeking. The present study aimed to relate digit ratio to pain perception using electric pain stimuli. 131 volunteers (69 females) participated. Two electric stimuli of different intensity were applied to the forearm. Digit ratio was obtained from the left and right hands and pain tolerance was assessed by means of visual analog scales. Additionally, participants completed personality questionnaires assessing sensation seeking and augmenting-reducing. Results indicated that males exhibited lower pain rating than females to the higher-intense electric stimulus; and both sensation seeking and stimulus reducing were associated with lower pain rating. Moreover, lower digit ratio (i.e., masculinized) of the right hand was negatively associated with nociception of the higher-intense electric shock only. Overall, this study supports the assumption that in utero gonadal hormone exposure might affect nociception, although, associations were generally small in magnitude and dependent on stimulus intensity.